The invention relates to a chain lock for link chains, having two essentially U-shaped lock parts which are releasably connected to one another and each have an inner limb and an outer limb which is connected to the latter via a yoke, the mutually facing sides of the inner and outer limbs being connected to one another in each case by three pairs of holding teeth in the closed position of the lock and a supporting and locking element for the lock parts being arranged between the mutually facing sides of the inner limbs in the region of the holding teeth of the central pairs of holding teeth which are designed to be stronger than the rest of the holding teeth.
A chain lock of the above type is known from DE 32 07 629 C2 with regard to its basic construction. The known chain lock is distinguished by a favourable distribution of the forces to be transmitted over the different pairs of holding teeth. Regardless of its advantageous design, the strength values which can be achieved with the known lock are still appreciably lower than the strength values exhibited by the links of the chain strands to be connected. Various approaches have been tried in the attempt to approximate the strength values of the lock to the strength values of chain links of the same quality category. One of the improvement possibilities is known from DE 43 33 261 C1; it consists in plastically deforming the region of the transition between the tooth flanks and the tooth interstices of the lock parts with the aid of a pressing or percussion tool in order, in this way, largely to compensate critical tensile direct stresses, occurring from the outset in the region mentioned, by means of compression stresses for the purpose of increasing dynamic strength.